The demand for high capacity rechargeable batteries is strong. Many applications, such as aerospace, medical devices, portable electronics, and automotive, require high gravimetric and/or volumetric capacity cells. Lithium ion technology demonstrated significant promises in this regard. However, the lithium ion technology is primarily based on graphite negative electrodes, and graphite has theoretical capacity of only about 372 mAh/g during lithiation.
Silicon is an attractive insertion material for lithium and other electrochemically active ions. A theoretical capacity of silicon in lithium ion cell has been estimated at about 4200 mAh/g during lithiation. Yet silicon and some other high capacity electrode materials have not been widely used or commercially implemented. One of the main reasons is substantial changes in volume during cycling. For example, silicon swells as much as 400% when it is charge close to its theoretical capacity. Volume changes of this magnitude can cause substantial stresses in active material structures resulting in fractures and pulverization, loss of electrical connections within the electrode, and capacity fading of the battery. Overall, there is a need for improved application of high capacity active materials in battery electrodes that minimize the drawbacks described above.